000 AXPZ20 KNHC 200355 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Tue Mar 20 2018 Tropical Weather Discussion for the eastern Pacific Ocean from the Equator to 32N, east of 140W. The following information is based on satellite imagery, weather observations, radar, and meteorological analysis. Based on 0000 UTC surface analysis and satellite imagery through 0300 UTC. ...SPECIAL FEATURES... Gale Warning: A weakening cold front from 30N129W to 20N140W is preceded by strong southerly flow north of 26N within 180 nm E of the front, with seas to 12 ft. A deepening surface low pres system NW of the area near 33N143W will drop SE tonight behind the cold front, dragging a second cold front into the discussion area accompanied by near gale force westerly winds. The pressure gradient will tighten around the southern semicircle of the low, with winds increasing to minimal gale force near 0900 UTC Tue morning, with associated seas of 15 to 17 ft. The low pres will lift north of the area Tue afternoon with winds diminishing to 20-30 kt, and 20 kt or less by early Wed. Large NW swell will propagate southeastward through Sat. Please refer to the Pacific high seas forecast for more details on this upcoming event under AWIPS/WMO headers MIAHSFEP2/FZPN03. Gulf of Tehuantepec Gale Warning: Strong to near-gale north flow will surge into the gulf early Wed morning, then increase to minimal gale force Wed night. Gale conditions are then expected to continue through Fri morning, with seas building to a maximum of around 12 ft. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 08N85W to 05N92W to 05N103W. The ITCZ axis continues from 05N103W to 06N140W. Scattered moderate isolated strong convection is noted within 30 nm either side of the ITCZ axis between 115W and 125W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Surface high pressure W of the northern Baja Peninsula extends a ridge axis S to near 19N. The ridge will shift southeast through Tue night, supporting fresh to locally strong northerly winds on Jalisco, Mexico offshore waters between 105W and 107W. Gentle to moderate northerly winds in the Baja offshore waters will become light to gentle Tue night as the ridge weakens. Gulf of California: Fresh to locally strong northwest flow is forecast across the southern half of the gulf waters through Tuesday evening accompanied by seas to 7 ft. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Fresh to strong northeast winds will develop downstream of the Gulf of Papagayo Tue night with seas building to 7 ft. Stronger winds are expected Wed night through Sat night with seas building to 11 ft. Fresh to strong northerly winds are expected downstream of the Gulf of Panama Wed night through Sat night. Light to gentle offshore flow will prevail elsewhere. Gulf of Panama: Fresh to strong northerly winds are expected downstream of the Gulf of Panama Wed night through Sat night. Light to gentle offshore flow is expected elsewhere through the weekend. REMAINDER OF THE AREA... Please see see Special Features Section above for details on gale force winds expected to affect the NW portion of the area. A progressive pattern will continue to impact the the northwest portion of the area well into the weekend. A deep layer low pres system located NW of the area is preceded by deep mid to upper level moisture. Clouds and precipitation associated the the low pres system will advance eastward towards southern California and the northern and central Baja California through Wed. $$ Mundell